The present invention relates to a connector for electrical cables and, more particularly, to a connector for attaching armored electrical cables to enclosures.
Armored electrical cables may be used in a wide variety of applications. They are particularly suited for environments in which it is essential for the wiring to be isolated from the surrounding environment. The conventional construction of such cable permits it to be used in environments which are referred to as hazardous locations. Such locations had traditionally been serviced with rigid metal conduit. In recent years, however, when permitted by applicable electrical code, armored cable may be used in place of rigid conduit. Rigid conduit is typically more difficult and more expensive to install than armored cable, therefore, it is desirable to use such cable when permitted.
Armored cable typically includes an electrically conductive flexible metal casing which protects the conductors running within from abrasion, impacts and the like. In addition, the metal casing permits the cable to be grounded throughout its length. An outer plastic or rubber sheath typically covers the metal casing thereby adding water proof protection to the cable as well as protecting the metal sheathing from corrosive elements.
When armored cables are connected to, or terminated in, metal enclosures, special connectors are typically employed. As is usually required by the applicable electrical code, such connectors provide electrical grounding continuity between the flexible metal casing and the enclosures. In addition, such connectors provide adequate physical retention of the cable and sealing moisture and dust from the enclosure.
Existing armored cable connectors are typically bulky in size. Such connectors often have numerous parts making the connector expensive to manufacture and time consuming to install. In addition, cable connectors typically can only accommodate a limited range of cable sizes. This requires a manufacturer to produce a wide variety of connectors in order to have a suitable connector available to accommodate the wide range of commercially available armored cables. Additionally, prior art armored cable connectors typically have two portions, a connector body and gland nut, which are threadedly engaged. As the two portions are threaded together, the armored cable has a tendency to twist.
Prior art armored cable connectors typically employ an elastomeric O-ring in order to provide the necessary sealing between the outer diameter of the cable and the connector. Such a design contributes to the two significant problems set forth above. The O-rings typically have an inside diameter substantially similar to the outside diameter of the cable and an outside diameter similar to the inside diameter of the connector piece in which it is disposed. When the connector body and gland nut are threaded together, the O-ring is deformed into forced sealing engagement with the cable. However, since an O-ring may only be slightly diametrically contracted without being damaged, only a narrow range of cable size may be accommodated by a particular connector. Additionally, as the gland nut portion of the connector is rotated onto the body portion of the connector and the O-ring begins to engage the cable, a torque is applied to the cable causing it to rotate. This rotation of the cable may result in its being damaged especially its outer sheathing.
Accordingly, there is a need for an armored cable connector which is capable of accommodating a wide range of cable sizes and which does not rotate the cable upon securing the connector components.
It is an object of the present invention to provide a connector for securing armored cable.
It is a further object of the present invention to provide a connector having a body portion, gland nut and a sealing ring for sealing about an armored cable.
It is still a further object of the present invention to provide a connector having a friction isolation device surrounding the sealing ring for preventing the transmission of torque from the gland nut to the cable when the gland nut is treaded onto the body.
It is yet a further object of the invention to provide a connector having a sealing ring with a U-shaped groove annularly extending about an outer surface of the sealing ring.
In the efficient attainment of these and other object, the present invention provides a connector for an armored cable including a connector body having a generally longitudinal opening extending therethrough and having a first end, a gland nut telescopically engageable with the first end of the connector body, the gland nut having a first end, the gland nut first end having an aperture for receiving the armored cable. The connector further includes a sealing ring positionable within the gland nut and having an inner annular surface engagable with the armored cable for seating about same on an opposed outer annular surface. The sealing ring has an annular groove formed about an outer surface thereof, and the groove permits the sealing ring to diametrically contract upon linear compression of the sealing ring. In addition an isolating device is provided that is positionable about the sealing ring for frictionally isolating the sealing ring from the gland nut and permitting the gland nut to rotate substantially independently ofthe sealing ring.